Television system



Patented Nov. 15, I938 UNITED STATES PATENT OFFICE' TELEVISION SYSTEM August Karolus, Leipzig, Germany, assignor to Radio Corporation of America, a corporation of Delaware Application April 8, 1935, Serial No. 15,156

I In Germany April 19, 1934 3 Claims. (01. 178-'7.6) The present invention relates to television sys- For the purpose of considering the description terns and particularly to apparatus for use at the following it will be assumed that the transmitter receiver end of such systems. is of the form suggested in my above named co- More specifically, the invention covers a syspending application and, so considered, a number 5 term and circuit arrangement for operating panof paralleled photoelectrically controlled picture 5 els or mosaics of luminous. cells upon which an transmission channels equal to the number N of electro-optical image is to be produced. such voltage sources I, II, III is provided,

Still further, the invention is. concerned with a each of the said channels being called upon to circuit scheme adapted to operate a picture retransmit sequentially the brightness values of the creating surface used in picture telegraphy, telepicture elements or elementary areas contained in 10 vision systems, advertising devices and the like by a vertical line or strip of the frame. For this making use of the so-called cell-screen principle. purpose, at the sending end, the picture to be Still other aims and objects of the invention transmitted is caused to move, 8- s d s l se will become apparent and suggest themselves to by my above named copending application, by

5 those skilled in this art by reading the following t e a e y of a mirror w l v a r w of N specification in connection with the accompanymany photoelectric cells which are coordinated ing drawing wherein Fig. 1 shows schematically to the N many voltage sources I, II, III. There one form of receiver panel or mosaic for reconare, therefore, interposed N y p fi structing the electro-optical image and Fig. 2 he d st bution of e e fm Occurring in h w a modification of t mosaic or panel synchronism with the picture scanning in the 20 arrangement f Fi 1, transmitter over the N many luminous cells con- Referring to the drawing, the i e-created pictained in each vertical strip or line is insured by ture as produced by the devices of Figs. 1 and 2 the aid of a change-over switch U. The switch comprises a large number of similar intensity- U is caused to Sweep Over M y o a s 2 controlled luminous cells designated for conven- 3" with which the horizontal colience as a1, d2, d3 b1, b2, b3 c1, c2, lector leads e co nectedc3 which in vertical direction are in Hence, the number of elementary areas of the single-pole connection with the collecting leads picture ou ts to, M t mes N, Where M=the I, 2, 3 and in horizontal direction also in mb r of pic r s l s r elemental strips n single-pole connection with the collecting wires N=ihe number of picture elements D e 0 30 I, 2', '3' etc. elemental strip or in the special instance where As shown by the drawing, each one of the verthe number of elemental areas equals N tical collector wires is united with the terminals Since e cui Organization llustrated in of an exciting voltage source I, II, III Figs. 1 and 2 which will be readily understandable subjected to control by the transmitter. The makes it p si l to i ze ly a ngle switch various sources I, II, III, etc., may be considered, Comprising M Contacts, it W e een that for for example, as embodying a resistance element a p c u e p sing 10,000 elementary areas, traversed by a variable current, the secondary y 100 Segment-S Will be q d Ov Which a winding of an anode transformer of a controlled Single d u r arm 0 Wiper is m de to move.

40 or regulated thermionic tube amplifier, or the w cc d g t e p se invention 40 like. an essential simplification of the kind herein- The signals for operating a receiver device of before outlined in the circuit organization and in the nature herein described are assumed to origipe t on o a m l t e panel l e p ca y nate from a transmitter arrangement of the gen- D SS bIe O ly W the following precautionary era} form and type shown and described by my measures are adopted! If the constituent lumi- 45 copending application Serial No. 12,536, filed 110118 s 1, a3 b3 March 23, 1935,now Patent No. 2,109,196, granted 1, 02, a a, s before described, are Feb. 22, 1938 (corresponding to German applicaunited with the horizontal and vertical collector tion Serial No. K. 133,651, dated March 26, 1934, Wir it W ll e seen that a number of other Docket 9598) although other suitable forms of groups will be connected in parallel to the partic- 50 transmitter devices such as are known and used ular luminous cell, for example, cell at which at a may be substituted. Such modified forms of given instant is asumed to be energized or er.- transmitters may be of the cathode ray type as cited. One of these shunt paths, for instance, disclosed by Zworykin, for example, or mechanis brought from the collector Wire I by way or .icaltypes commonly used for demonstrations. lamps b1, b2, and (12; another path leads by way 55 of lamps c1, 02, a2; and, obviously, still other paths may be traced without difilculty. Another danger arises in the case where alternating voltages of the various voltage sources I, II, III

are not in phase, but in phase opposition, i. e., act in series in reference of certain luminous cells. For instance, voltages in phase opposition which arise at the terminals I and II resulting in an integrated voltage would tend to become equalized by way of lamps or light sources or and oz.

The two risks hereinbefore mentioned are obviated according to this invention by providing for each individual luminous cell a series connection with a rectifier or else by imparting a rectifier characteristic to each of the cells proper. This latter situation will be present, for instance, in the case of glow tubes which, as a result of dissimilar shape or surface size of the electrodes allow of the passage in one direction of a far stronger discharge current than in the opposite sense. If incandescent lamps are employed as the various luminous cells forming the complete panel, then small-sized dry rectifiers such as cuprous-oxide rectifiers are preferably connected in series. with each lamp. These individual rectifiers must be proportioned so as to suit the average working current of the associated incandescent lamp. The effect intended by the series connection of a uni-directionally transmitting or conducting element or the rectifier action ingaseous discharges is indicated in the drawing schematically by the use of an arrowhead in connection with each of the various luminous cells.

By reference to the diagram indicative of the paths of the current it will be readily understood that in this manner both undesirable shunts as well as short-circuits are avoided seeing that in each instance a rectifying means is contained in each path or chain which would have to be traversed in the blocking or non-conducting sense if this were to happen. The said means, for instance, in the case of the shunt to arby way of b1, b2, (12, would be the cell or combination be. In fact, it is only by virtue of this object and feature of the invention that the simplification of the switch mechanism is made possible and practicable to an extent as before described, while the undisturbed excitation un- -der proper phase conditions of each luminous cell in relation to the decomposition or scanning of the picture at the sending end will be quantitatively secured.

In arrangements of this kind, as experience has taught, it. is difllcult to safeguard the segments I, 2", 3", of the change over switch U from the destructive action of sparking, especially when the constituent luminous cells of the recreating surface require comparatively high working voltages and allow transiently of the flow of strong excess currents which become integrated in the plurality of simultaneously excited cells. According to the invention, there fore, for the object of relieving the contacts of the switch device U, a joint input tube 4 is connected in series with the said switch which will cause interruption at the proper time. This tube 4 which is controlled by the grid 5, by the aid of a synchronous alternating voltage, is always rendered currentless or non-energized a brief instant prior to the point when the rotating contact slides away from the particular segment that has been contacted. Interruption is effected in this case in the absence of sparking inasmuch as it. really occurs inside the tube 4. If the voltage sources I, II, III constitute the secondary windings of plate transformers of separate amplifier tubes, it will also be recommendable instead of using a common tube 4 (which, in a circuit organization such as illustrated would have to be dimensioned for very considerable currents) to block the various power tubes or input tubes coordinated to the sources I, II, III, at the grid end, and all that is required therefor is an alternating voltage which is synchronous and which operates at the proper phase so that, at the instant when the contact is broken, the potentials prevailing at I, II and III will be off.

It is evident from the foregoing description that this invention provides ways and means for obtaining electro-optical images of extremely great brilliancy. Due to the fact that each lamp is actually excited l/MN of total time to produce each complete image it is possible to increase the power input MN times the normal value without changing the total power consumption. Previously, this could not be done, so far as applicant is aware, because the instantaneous peak power was excessive for successful commutation. Applicants invention, however, permits successful commutation of this instantaneous high power and thus a picture of high brilliance results. To refer to one specific example, assume, for instance, that each of the lamps a1, a2, a3 b1, b2, b3, etc., is of the 6 volt, 50 m. a. type. Since the time for switching from line to line with the commutating distributor U is only of the time for producing a complete picture (still assuming a 100 line picture) it can be seen that the lamps can each operate during the period of switching at 60 volts and 500 m. a. without increasing the total power. Thus, it is clearly apparent that the mosaic panel when. operating as above described is capable of producing controlled intensity electro-optical images of great brilliancy.

Many modifications and changes may be made in the system above described without departing from the spirit and scope of the foregoing disclosure and I believe myself to be entitled to make and use any and all of such modifications as fall fairly within the scope of the claims, wherein I claim as new the following:

1. In image reproducing apparatus wherein there are provided a plurality of light sources arranged in mesh-like manner, a series of ordinate and abscissa conductors connecting said light sources in said mesh-like manner, a plurality of signal controlled energizing means connected individually with one series of said conductors and. a distributor connected so as to energize sequentially upon rotation the other series of conductors and thereby cause the illumination of the light source at the intersection point of the energized conductors of each set and means for limiting the flow of signal energy to a single point only in said mesh instantaneously.

2. In a television receiver panel, a plurality of rectifiers, a plurality of independent sets of conductors arranged in intersecting patterns, a plurality of individual means each adapted to produce light when energized each joined in series with one of said rectifiers, each of said series circuits being connected at an intersection of said aforementioned conductors, means for energizing one of said sets of conductors with energy varying in accordance with the image to be reproduced, means for sequentially connecting the other of said sets of conductors, and means for de-energizing said sequential joining means sub- 7 stantially at the time of disconnection from any conductor.

3. In a television receiver panel, a plurality of rectifiers, a plurality of independent sets of conductors arranged in intersecting patterns, a plurality of individual means each adapted to produce light when energized each joined in series with one of said rectifiers, each of said series circuits being connected at an intersection of said 10 aforementioned conductors, means for energizing one of said sets of conductors with energy varying in accordance with the image to be reproduced, means for sequentially connecting the other of said sets of conductors comprising a retating switch arm adapted to sequentially join each of said conductors, and means for de-energizing said sequential joining means substantially at the time of disconnection from any conductor.

AUGUST KAROLUS. 

